1. Field of the Invention
The present invention relates to a video camera system with a detachable lens unit.
2. Related Background Art
Recent innovations of video equipment, e.g., video cameras, allow improved operability, and multi-functions. Recently, a remarkable one of such innovations concerns an exchangeable lens of a video camera.
In a video camera system of this type, both a camera unit and a lens unit detachable from the camera unit incorporate microcomputers, and bidirectional communications of control information are made between these units. Thus, the camera unit controls focus, iris, zoom functions, and the like in the lens unit.
More specifically, a control information communication system according to predetermined agreements is employed, in which the camera unit fetches various pieces of information from the lens unit, and transmits a control command to the lens unit, thereby controlling the lens unit.
However, in this prior art, if the control method of the focus, iris, zoom functions, and the like in the lens unit is improved in the future, and a new function is added, or if the format of control information is changed, and the control information communication system based on the above-mentioned agreements undergoes version-up, i.e., updating of capabilities, compatibility between the old and new versions is not assured. When the camera unit and the lens unit have different versions, a control command from the camera unit may not be decoded by the lens unit, or wrong control may be made. When products of both the old and new versions are present on the market, compatibility between camera units and lens units cannot be realized. Such situation not only confuses users, but also considerably impairs the degree of accomplishment of the system itself.